Method for producing silicone-treated polymers

ABSTRACT

Silicone-containing addition polymers having numerous uses are prepared by polymerizing addition polymerizable monomers in the presence of a silicone-containing polyvinyl alcohol, and/or by adding a silicone-containing polyvinyl alcohol to an aqueous addition polymer dispersion prior to spray drying, the silicone-containing polyvinyl alcohol containing at least one polymerizable group.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to PCT Appln. No. PCT/EP2003/14491filed Dec. 18, 2003, and to German application 103 01 975.8 filed Jan.20, 2003.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a process for preparing silicone-modifiedpolymers in the form of their aqueous polymer dispersions or in the formof their polymer powders, to their use, and to protective colloidscomprising silicone units.

2. Description of the Related Art

Organosilicon compounds such as organosiloxane polymers are used forhydrophobicizing polymers of ethylenically unsaturated monomers. Suchhydrophobically modified polymers are used in many fields in the form oftheir polymer powders, in particular water-redispersible polymerpowders, or as aqueous polymer dispersions. They are employed as bindersin coating compositions or adhesives, in particular in the buildingsector and textile sector, and also as binders in cosmetics and haircareproducts.

It is known from WO-A 95/20626 that water-redispersible polymer powderscan be modified by addition of noncopolymerizable organosiliconcompounds. EP-A 0352339 describes protective surface coatings forconcrete constructions, which comprise copolymers ofdivinylpolydimethylsiloxane with acrylate esters or methacrylate estersand with vinyl- or acryl-functional alkoxysilanes as a solution inorganic solvent. EP-B 771826 describes aqueous binders for coatings andadhesives which are based on emulsion polymers of vinyl esters, acrylicor methacrylic esters or vinyl aromatics containing polysiloxanes havingunsaturated radicals, for example vinyl, acryloxy or methacryloxygroups, as crosslinkers. EP-A 943634 describes aqueous latices for useas coating compositions, which are prepared by copolymerization ofethylenically unsaturated monomers in the presence of a silicone resincontaining silanol groups. EP-A 1095953 describes silicone-grafted vinylcopolymers in which a carbosiloxane dendrimer is grafted onto the vinylpolymer.

It is known from DE-A 19951877 and WO-A 99/04750 thatsilicone-containing polymers are obtainable by polymerization ofethylenically unsaturated monomers in the presence of a linearpolydialkylsiloxane having polyalkylene oxide side chains. US-A 5216070describes a process for the inverse emulsion polymerization ofcarboxyl-functional monomers, in which linear polydialkylsiloxaneshaving polyalkylene oxide side chains are used as an emulsifier.

DE-A 4240108 describes a polymerization process for preparingpolysiloxane-containing binders for use in dirt-repellent coatings, inwhich the monomers are polymerized in the presence of an OH—, COOH— orepoxy-functional polydialkylsiloxane which may additionally containpolyether groups. DE-A 10041163 discloses a process for producinghair-cosmetic formulations, in which vinyl esters are polymerized in thepresence of a polyether-containing compound, for examplepolyether-containing silicone compounds.

A disadvantage of the silicone-modified emulsion polymers described inthe prior art is a strong tendency to hydrolyze and to undergouncontrolled crosslinking, which in some applications may indeed bedesirable and is subsequently reinforced by addition of silane andcatalyst, but in the case of surface coating dispersions or when theemulsion polymers are used as coating compositions leads to undesirablegel particles, “specks” and insoluble constituents. Furthermore, thesilicone-containing emulsion polymers known hitherto are often notalkali-resistant, since silicones are known to be unstable in analkaline medium. For this reason, the hydrophobicity and the associatedpositive properties of the systems described hitherto decrease greatlyafter a prolonged period of time. Finally, the introduction of a largeamount of silanes or silicones into the emulsion polymers results inestablishment of an unsatisfactory particle size distribution, i.e. theparticles become too large and the polymer becomes inhomogeneous, whichcan lead to serum formation or phase separation. Furthermore, coagulumformation can also occur.

SUMMARY OF THE INVENTION

It was an object of the invention to develop polymers which arehydrolysis-resistant and hydrophobic and therefore weathering-stable,water-repellent and nonsoiling and also have a good water vaporpermeability and a high wet abrasion resistance. A further object was toprovide a process by means of which hydrophobically modified polymershaving a narrow particle size distribution and no coagulation can beobtained. These and other objects are achieved by polymerization of oneor more unsaturated monomers in the presence of a silicone-containingpolyvinyl alcohol copolymer of defined composition.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The invention provides a process for preparing silicone-modifiedpolymers in the form of their aqueous polymer dispersions or in the formof their polymer powders by means of free-radical polymerization ofethylenically unsaturated monomers in an aqueous medium and, ifappropriate, drying of the polymer dispersions obtainable in this way,characterized in that one or more monomers from the group consisting ofvinyl esters of unbranched or branched alkylcarboxylic acids having from1 to 15 carbon atoms, methacrylic esters and acrylic esters of alcoholshaving from 1 to 15 carbon atoms, vinyl aromatics, olefins, dienes andvinyl halides are polymerized, with a silicone-containing vinyl alcoholcopolymer comprising

-   a) from 0 to 60% by weight of one or more monomer units of vinyl    esters of unbranched or branched alkylcarboxylic acids having from 1    to 15 carbon atoms,-   b) from 20 to 99.5% by weight of vinyl alcohol units,-   c) from 0.5 to 70% by weight of monomer units of one or more    silicones having the general formula R¹    _(a)R_(3-a)SiO(SiR₂O)_(n)SiR_(3-a)R¹ _(a), where the radicals R are    identical or different and are each a monovalent, substituted or    unsubstituted alkyl radical or alkoxy radical having in each case    from 1 to 18 carbon atoms, R¹ is a polymerizable group, a is 0 or 1    and n is from 10 to 1000, and also, if desired, further auxiliary    monomers, where at least one silicone contains at least one radical    R¹ and the percentages by weight add up to 100% by weight,    being added before, during or after their polymerization.

Suitable vinyl esters are vinyl esters of unbranched or branchedcarboxylic acids having from 1 to 15 carbon atoms. Preferred vinylesters are vinyl acetate, vinyl propionate, vinyl butyrate, vinyl2-ethylhexanoate, vinyl laurate, 1-methylvinyl acetate, vinyl pivalateand vinyl esters of α-branched monocarboxylic acids having from 5 to 13carbon atoms, for example VeoVa9^(R) or VeoVa10^(R) (trade names ofShell). Particular preference is given to vinyl acetate and the greatestpreference is given to a combination of vinyl acetate with α-branchedmonocarboxylic acids having from 5 to 11 carbon atoms, e.g. VeoVa10.

Suitable monomers from the group of esters of acrylic acid ormethacrylic acid are esters of unbranched or branched alcohols havingfrom 1 to 15 carbon atoms. Preferred methacrylic esters or acrylicesters are methyl acrylate, methyl methacrylate, ethyl acrylate, ethylmethacrylate, propyl acrylate, propyl methacrylate, n-butyl, isobutyland t-butyl acrylate, n-butyl, isobutyl and t-butyl methacrylate,2-ethylhexyl acrylate, norbornyl acrylate.

Particular preference is given to methyl acrylate, methyl methacrylate,n-butyl, isobutyl and t-butyl acrylate, 2-ethylliexyl acrylate andnorbornyl acrylate.

Suitable dienes are 1,3-butadiene and isoprene. Examples ofcopolymerizable olefins are ethene and propene. Vinylaromatics which canbe copolymerized are styrene and vinyltoluene. From the group of vinylhalides, use is usually made of vinyl chloride, vinylidene chloride orvinyl fluoride, preferably vinyl chloride.

If desired, from 0.05 to 30% by weight, based on the total weight of theethylenically unsaturated monomers, of auxiliary monomers can becopolymerized. Examples of auxiliary monomers are ethylenicallyunsaturated monocarboxylic and dicarboxylic acids or salts thereof,preferably crotonic acid, acrylic acid, methacrylic acid, fumaric acidand maleic acid; ethylenically unsaturated carboxamides and carboxylicnitriles, preferably acrylamide and acrylonitrile; monoesters anddiesters of fumaric acid and maleic acid, e.g. the diethyl anddiisopropyl esters, and also maleic anhydride, ethylenically unsaturatedsulfonic acids or salts thereof, preferably vinylsulfonic acid,2-acrylamido-2-methylpropanesulfonic acid. Further suitable auxiliarymonomers are cationic monomers such as diallyldimethylammonium chloride(DADMAC), 3-trimethylammoniopropyl(meth)acrylamide chloride (MAPTAC) and2-trimethylammonioethyl (meth)acrylate chloride. Also suitable are vinylethers, vinyl ketones, further vinylaromatic compounds which may alsocontain heteroatoms.

Suitable auxiliary monomers also include polymerizable silanes ormercaptosilanes. Preference is given to γ-acryl- orγ-methacryloxypropyltri(alkoxy)silanes,α-methacryloxymethyltri(alkoxy)silanes,γ-methacryloxy-propylmethyldi(alkoxy)silanes,vinylalkyldi(alkoxy)silanes and vinyltri(alkoxy)silanes, with, forexample, methoxy, ethoxy, methoxyethylene, ethoxyethylene,methoxypropylene glycol ether or ethoxypropylene glycol ether radicalsbeing able to be used as alkoxy groups. Examples arevinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane,vinyltriisopropoxysilane, vinyltris(1-methoxy)isopropoxysilane,vinyltributoxysilane, vinyltriacetoxysilane,3-methylacryloxypropyltrimethoxysilane,3-methacryloxypropylmethyldimethoxysilane,methacryloxymethyltrimethoxysilane,3-methacryloxypropyltris(2-methoxyethoxy)silane, vinyltrichlorosilane,vinylmethyldichlorosilane, vinyltris(2-methoxyethoxy)silane,trisacetoxyvinylsilane, 3-(triethoxysilyl)propyl(succinicanhydride)silane. Preference is also given to3-mercaptopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and3-mercaptopropylmethyldimethoxysilane.

Further examples are functionalized (meth)acrylates, in particularepoxy-functional (meth)acrylates such as glycidyl acrylate, glycidylmethacrylate, allyl glycidyl ether, vinyl glycidyl ether, orhydroxyalkylfunctional (meth)acrylates such as hydroxyethyl(meth)acrylate, or substituted or unsubstituted aminoalkyl(meth)acrylates, or cyclic monomers such as N-vinylpyrrolidone.

Also suitable are polymerizable silicone macromers having at least oneunsaturated group, e.g. linear or branched polydialkylsiloxanes whichhave a C₁-C₆-alkyl radical and a chain length of from 10 to 1000,preferably from 50 to 500, SiO(C_(n)H_(2n+1))₂ units and contain one ortwo terminal polymerizable groups (functional groups) or one or morepolymerizable groups in the chain. Examples are polydialkylsiloxaneshaving one or two vinyl, acryloxyalkyl, methacryloxyalkyl ormercaptoalkyl groups, where the alkyl groups can be identical ordifferent and contain from 1 to 6 carbon atoms. Preference is given toα,ω-divinylpolydimethylsiloxanes,α,ω-di(3-acryloxypropyl)polydimethylsiloxanes,α,ω-di(3-methacryloxypropyl)polydimethylsiloxanes,α-monovinylpolydimethylsiloxanes,1-mono(3-acryloxypropyl)polydimethylsiloxanes,α-mono(3-methacryloxypropyl)polydimethylsiloxanes and also siliconeshaving chain-transferring groups such asα-mono(3-mercaptopropyl)polydimethylsiloxanes or α,ω-di(3-mercaptopropyl)polydimethylsiloxanes. The polymerizable siliconemacromonomers described in EP-A 614924 are also suitable.

Further examples are precrosslinking comonomers such as multipleethylenically unsaturated comonomers, for example divinyl adipate,divinylbenzene, diallyl maleate, allyl methacrylate, butanedioldiacrylate or triallyl cyanurate, or postcrosslinking comonomers, forexample acrylamidoglycolic acid (AGA), methyl methylacrylamidoglycolate(MAGME), N-methylolacrylamide (NMA), N-methylolmethacrylamide, allylN-methylolcarbamate, alkyl ethers such as the isobutoxy ether or esterof N-methylolacrylamide, of N-methylolmethacrylamide and of allylN-methylolcarbamate.

The ethylenically unsaturated monomers are preferably selected so thataqueous copolymer dispersions and aqueous redispersions of copolymerpowders which without addition of film forming aids have a minimum filmformation temperature MFT of <10° C., preferably <5° C., in particularfrom 0° C. to 2° C., are obtained. A person skilled in the art will knowon the basis of the glass transition temperature T_(g) which monomers ormonomer mixtures can be used for this purpose. The glass transitiontemperature T_(g) of the polymers can be determined in a known manner bymeans of differential scanning calorimetry (DSC). The T_(g) can also becalculated beforehand to a good approximation by means of the Foxequation. According to Fox T. G., Bull. Am. Physics Soc. 1, 3, page 123(1956): 1/T_(g)=x1/T_(g)1+x2/T_(g)2+ . . . +xn/T_(g)n, where xn is themass fraction (% by weight/100) of the monomer n and T_(g)n is the glasstransition temperature in kelvin of the homopolymer of the monomer n.T_(g) values of homopolymers are given in the Polymer Handbook 2^(nd)Edition, J. Wiley & Sons, New York (1975).

Preference is given to the copolymer compositions listed below:

-   polymers of vinyl acetate;-   vinyl ester copolymers of vinyl acetate with further vinyl esters    such as vinyl laurate, vinyl pivalate, vinyl-2-ethylhexanoate, vinyl    esters of an alpha-branched carboxylic acid, in particular vinyl    esters of Versatic acid (VeoVa9^(R), VeoVa10^(R));-   vinyl ester-ethylene copolymers such as vinyl acetate-ethylene    copolymers which may further comprise other vinyl esters such as    vinyl laurate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl esters    of an alpha-branched carboxylic acid, in particular vinyl esters of    Versatic acid (VeoVa9^(R), VeoVa10^(R)), or diesters of fumaric acid    or maleic acid;-   vinyl ester-ethylene copolymers such as vinyl acetate-ethylene    copolymers which may further comprise vinyl esters such as vinyl    laurate, vinyl pivalate, vinyl 2-ethylhexanoate, vinyl esters of an    alpha-branched carboxylic acid, in particular vinyl esters of    Versatic acid (VeoVa9^(R), VeoVa10^(R)) and a polymerizable silicone    macromer;-   vinyl ester-ethylene-vinyl chloride copolymers, with preference    being given to vinyl acetate and/or vinyl propionate and/or one or    more copolymerizable vinyl esters such as vinyl laurate, vinyl    pivalate, vinyl 2-ethyl hexanoate, vinyl esters of an alpha-branched    carboxylic acid, in particular vinyl esters of Versatic acid    (VeoVa9^(R), VeoVa10^(R)), being present as vinyl esters;-   vinyl ester-acrylic ester copolymers with vinyl acetate and/or vinyl    laurate and/or vinyl esters of Versatic acid and acrylic esters, in    particular butyl acrylate or 2-ethylhexyl acrylate, which may    further comprise ethylene;-   acrylic ester copolymers, preferably with n-butyl acrylate and/or    2-ethylhexyl acrylate;-   methyl methacrylate copolymers, preferably with butyl acrylate    and/or 2-ethylhexyl acrylate, and/or 1,3-butadiene;-   styrene-1,3-butadiene copolymers and styrene-(meth)acrylic ester    copolymers such as styrene-butyl acrylate, styrene-methyl    methacrylate-butyl acrylate or styrene-2-ethylhexyl acrylate, with    n-butyl, isobutyl, tert-butyl acrylate being able to be used as    butyl acrylate.

The greatest preference is given to vinyl ester-ethylene copolymers suchas vinyl acetate-ethylene copolymers and copolymers of vinyl acetate andethylene and vinyl esters of a α-branched carboxylic acid having 9 or 10carbon atoms (VeoVa9^(R), VeoVa10^(R)), and in particular copolymers ofvinyl acetate, ethylene, vinyl esters of an α-branched carboxylic acidhaving 9 or 10 carbon atoms (VeoVa9^(R), VeoVa10^(R)) withcopolymerizable silicone macromers; having an ethylene content ofpreferably from 2 to 30% by weight, which may further compriseadditional auxiliary monomers in the amounts indicated.

The silicone-containing polymers are prepared by means of free-radicalpolymerization in an aqueous medium, preferably emulsion polymerization.The polymerization is usually carried out in a temperature range from20° C. to 100° C., in particular from 45° C. to 80° C. Initiation iseffected by means of the customary free-radical initiators, which arepreferably used in amounts of from 0.01 to 3.0% by weight, based on thetotal weight of the monomers. Initiators used are preferably inorganicperoxides such as ammonium, sodium, potassium peroxodisulfate orhydrogen peroxide, either alone or in combination with reducing agentssuch as sodium sulfite, sodium hydrogen sulfite, sodiumformaldehydesulfoxylate or ascorbic acid. It is also possible to usewater-soluble organic peroxides, for example t-butyl hydroperoxide,cumene hydroperoxide, usually in combination with reducing agents, orelse water-soluble azo compounds. In the copolymerization using gaseousmonomers such as ethylene and vinyl chloride, the polymerization iscarried out under pressure, generally at from 1 to 100 bar_(abs).

The silicone part is introduced into the polymers by adding asilicone-containing vinyl alcohol copolymer comprising

-   a) from 0 to 60% by weight of one or more monomer units of vinyl    esters of unbranched or branched alkylcarboxylic acids having from 1    to 15 carbon atoms,-   b) from 20 to 99.5% by weight of vinyl alcohol units,-   c) from 0.5 to 70% by weight of monomer units of one or more    silicones having the general formula R¹    _(a)R_(3-a)SiO(SiR₂O)_(n)SiR_(3-a)R¹ _(a), where the radicals R are    identical or different and are each a monovalent, substituted or    unsubstituted alkyl radical or alkoxy radical having in each case    from 1 to 18 carbon atoms, R¹ is a polymerizable group, a is 0 or 1    and n is from 10 to 1000, and also, if desired, further auxiliary    monomers, where at least one silicone contains at least one radical    R¹ and the percentages by weight add up to 100% by weight,    as protective colloid before, during or after the polymerization.

The proportion of vinyl ester is preferably from 3 to 35% by weight. Forthe proportion of vinyl alcohol, the range from 40 to 90% by weight ispreferred. The proportion of silicone units is preferably from 5 to 60%by weight, in particular from 9 to 50% by weight. n is preferably from20 to 500, particularly preferably from 40 to 200.

A preferred vinyl ester a) for preparing the silicone-containing vinylalcohol copolymer is vinyl acetate.

Examples of radicals R in the general formula R¹_(a)R_(3-a)SiO(SiR₂O)_(n)SiR_(3-a)R¹ _(a) are the methyl, ethyl,n-propyl, isopropyl, 1-n-butyl, 2-n-butyl, isobutyl, tert-butyl,n-pentyl, isopentyl, neopentyl, tert-pentyl radical, hexyl radicals suchas the n-hexyl radical, heptyl radicals such as the n-heptyl radical,octyl radicals such as the n-octyl radical and isooctyl radicals such asthe 2,2,4-trimethylpentyl radical, nonyl radicals such as the n-nonylradical, decyl radicals such as n-decyl radical, dodecyl radicals suchas the n-dodecyl radical and octadecyl radicals such as the n-octadecylradical, cycloalkyl radicals such as cyclopentyl, cyclohexyl,cycloheptyl and methylcyclohexyl radicals. The radical R is preferably amonovalent hydrocarbon radical having from 1 to 6 carbon atoms, e.g. amethyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, amyl or hexylradical, with particular preference being given to the methyl radical.

Preferred alkoxy radicals R are ones having from 1 to 6 carbon atoms,e.g. the methoxy, ethoxy, propoxy and n-butoxy radical, which may befurther substituted by oxyalkylene radicals such as oxyethylene oroxymethylene radicals. Particular preference is given to the methoxy andethoxy radicals. The alkyl radicals and alkoxy radicals mentioned for Rmay also be substituted, for example by halogen, mercapto groups,epoxy-functional groups, carboxyl groups, keto groups enamine groups,amino groups, aminoethylamino groups, isocyanato groups, aryloxy groups,alkoxysilyl groups and hydroxyl groups.

Suitable polymerizable groups R¹ are alkenyl radicals having from 2 to 8carbon atoms. Examples of such polymerizable groups are the vinyl,allyl, butenyl and also acryloxyalkyl and methacryloxyalkyl groups, withthe alkyl radicals having from 1 to 4 carbon atoms. Preference is givento the vinyl group, the 3-methacryloxypropyl group, the acryloxymethylgroup and the 3-acryloxypropyl group.

Preference is given to α,ω-divinylpolydimethylsiloxanes,α,ω-di(3-acryloxypropyl)polydimethylsiloxanes,α,ω-di(3-methacryloxypropyl)polydimethylsiloxanes. In the case of thesilicones substituted by only one unsaturated group, preference is givento α-monovinylpolydimethylsiloxanes,α-mono(3-acryloxypropyl)polydimethylsiloxanes,α-mono(acryloxymethyl)polydimethylsiloxanes,α-mono(3-methacryloxypropyl)polydimethylsiloxanes. In the monofunctionalpolydimethylsiloxanes, an alkyl or alkoxy radical, for example a methylor butyl radical, is located at the other end of the chain.

Preference is also given to mixtures of linear or brancheddivinylpolydimethylsiloxanes with linear or branchedmonovinylpolydimethylsiloxanes and/or unfunctionalizedpolydimethylsiloxanes (the latter have no polymerizable group), and alsomixtures of linear or branched monovinylpolydimethylsiloxanes withunfunctionalized polydimethylsiloxanes. The vinyl groups are preferablylocated at the end of the chain. Examples of such mixtures are siliconesof the solvent-free Dehesive®-6 series (branched) or Dehesive®-9 series(unbranched) of Wacker-Chemie GmbH. In the binary or ternary mixtures,the proportion of unfunctional polydialkylsiloxanes is up to 15% byweight, preferably up to 5% by weight; the proportion of monofunctionalpolydialkylsiloxanes is up to 50% by weight; and the proportion ofbifunctional polydialkylsiloxanes is at least 50% by weight, preferablyat least 60% by weight, in each case based on the total weight of thesilicone component.

Most preferred silicone units are α,ω-divinylpolydimethylsiloxanes andbinary mixtures of α,ω-divinylpolydimethylsiloxanes withα-monovinylpolydimethylsiloxanes and ternary mixtures ofα,ω-divinylpolydimethylsiloxanes and α-monovinylpolydimethylsiloxaneswith unfunctionalized polydimethylsiloxane.

Apart from these monomers, further auxiliary monomers can beadditionally copolymerized in the silicone-containing vinyl alcoholcopolymer. Suitable auxiliary monomers are those which have beenmentioned above for the polymers of ethylenically unsaturated monomers,in the amounts specified there.

Greatest preference is given to silicone-containing vinyl alcoholcopolymers comprising vinyl acetate, vinyl alcohol andpolydimethylsiloxane units. In general, the silicone-containingcopolymers are introduced in an amount of from 0.01 to 40% by weight,preferably from 0.1 to 10% by weight, before, during or after thepolymerization.

The preparation of the silicone-containing vinyl alcohol copolymers isdescribed in DE 10215962. It is carried out by polymerization of thevinyl esters indicated and the silicone units in a nonaqueous, organicsolvent, and subsequent hydrolysis of the resulting copolymers inalcoholic solution to introduce the vinyl alcohol units.

If the silicone-containing vinyl alcohol copolymer just described isintroduced as protective colloid before or during the polymerization,anionic and nonionic emulsifiers and also further protective colloidscan be used in addition to the silicone-containing vinyl alcoholcopolymer for stabilizing the polymers. Preference is given to usingnonionic or anionic emulsifiers, preferably a mixture of nonionic andanionic emulsifiers. As nonionic emulsifiers, preference is given tousing condensation products of ethylene oxide or propylene oxide withlinear or branched alcohols having from 8 to 18 carbon atoms,alkylphenols or linear or branched carboxylic acids having from 8 to 18carbon atoms, and also block copolymers of ethylene oxide and propyleneoxide. Suitable anionic emulsifiers are, for example, alkylsulfates,alkylsulfonates, alkylarylsulfates and also sulfates or phosphates ofcondensation products of ethylene oxide with linear or branched alkylalcohols which have from 5 to 25 EO units, alkylphenols and monoestersor diesters of sulfosuccinic acid. The amount of emulsifiers is from0.01 to 10% by weight, based on the total weight of the monomers used.

If appropriate, further protective colloids can be used in addition tothe silicone-containing vinyl alcohol copolymer. Examples of suitableprotective colloids are polyvinyl alcohols having a content of from 75to 95 mol %, preferably from 84 to 92 mol %, of vinyl alcohol units;poly-N-vinyl amides such as polyvinylpyrrolidones; polysaccharides suchas starches and also celluloses and their carboxymethyl, methyl,hydroxyethyl, hydroxypropyl derivatives; synthetic polymers such aspoly(meth)acrylic acid, poly(meth)acrylamide. Particular preference isgiven to using the polyvinyl alcohols mentioned. The protective colloidsare generally used in an amount of from 0.01 to 40% by weight, based onthe total weight of the monomers used.

If appropriate, the molecular weight can be controlled by means of thecustomary regulators, for example alcohols such as isopropanol,aldehydes such as acetaldehyde, chlorine-containing compounds,mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan,mercaptopropionic acid (esters). To set the pH, pH-regulating compoundssuch as sodium acetate or formic acid can be used in the preparation ofthe dispersion.

Regardless of the polymerization process, the polymerization can becarried out with or without use of seed lattices, with all or someconstituents of the reaction mixture being initially charged, or somecan be initially charged and one or more constituents of the reactionmixture can be metered in subsequently, or the polymerization can becarried out by the feed stream process without an initial charge. Thecomonomers and, if appropriate, the auxiliary monomers can all beinitially charged in the preparation of the dispersion (batch process),or part of the monomers is initially charged and the remainder ismetered in (semibatch process).

The silicone-containing vinyl alcohol copolymers can be initiallycharged or metered in to prepare the dispersion, or part is initiallycharged and the remainder is metered in. The surface-active substancescan be metered in alone or as a preemulsion with the comonomers.

In the copolymerization of gaseous monomers a), e.g. ethylene, thedesired amount is introduced by setting a particular pressure. Thepressure under which the gaseous monomer is introduced can be set to aparticular value at the beginning and can decrease during thepolymerization, or the pressure is kept constant during the entirepolymerization. The latter embodiment is preferred.

After conclusion of the polymerization, an after-polymerization can becarried out by known methods to remove residual monomers, for example bymeans of an after-polymerization initiated by a redox catalyst. Volatileresidual monomers and further volatile, nonaqueous constituents of thedispersion can also be removed by means of distillation, preferablyunder reduced pressure, and, if appropriate with inert entrainer gasessuch as air, nitrogen or steam being passed through or over the reactionmixture.

The aqueous dispersions obtainable by the process of the invention havea solids content of from 30 to 70% by weight, preferably from 45 to 65%by weight. To prepare polymer powders, in particular water-redispersiblepolymer powders, the aqueous dispersions, if appropriate after additionof protective colloids as atomization aid, are dried, for example bymeans of fluidized bed drying, freeze drying or spray drying. Thedispersions are preferably spray dried. Spray drying is carried out inconventional spray drying units, with atomization being able to becarried out by means of single-fluid, two-fluid or multifluid nozzles orusing a rotating disc. The outlet temperature is generally in the rangefrom 45° C. to 120° C., preferably from 60° C. to 90° C., depending onthe unit, the T_(g) of the resin and the desired degree of drying.

In general, the atomization aid is used in a total amount of from 3 to30% by weight, based on the polymeric constituents of the dispersion.Suitable atomization aids are the abovementioned protective colloids.Particular preference is also given to using the silicone-containingvinyl alcohol copolymers as atomization aid.

A content of up to 1.5% by weight of antifoams, based on the basepolymer, has frequently been found to be advantageous for atomization.To improve the blocking stability, the powder obtained can be mixed withan antiblocking agent (anticaking agent), preferably in an amount of upto 30% by weight, based on the total weight of polymeric constituents.Examples of antiblocking agents are Ca or Mg carbonate, talc, gypsum,silica, kaolins, silicates.

Emulsion polymers which are hydrophobic, stable to weathering,water-repellent, very stable and soiling-resistant and also have a goodwater vapor permeability are obtained.

The silicone-containing polymers in the form of their aqueousdispersions and in the form of their polymer powders, in particularwater-redispersible polymer powders, are suitable for use in adhesivesor coating compositions, for strengthening fibers or other particulatematerials, for example for the textile sector. They are also suitable asmodifiers and hydrophobicizing agents. They can also be usedadvantageously in the field of polishers and in cosmetics, e.g. in thehaircare field. They are also suitable as binders in adhesives andcoating compositions, and also as protective coating, e.g. for metals,films, wood, or as release coating, e.g. for paper treatment. They areparticularly useful as binders for paints, adhesives and coatingcompositions in the building sector, for example in tile adhesives andthermal insulation adhesives, and in particular for use in low-emissionplastic emulsion paints and plastic emulsion renders, both for interiorand exterior use. The formulations for emulsion paints and emulsionrenders are known to those skilled in the art, and generally comprisefrom 5 to 50% by weight of the silicone-containing polymers, from 5 to35% by weight of water, from 5 to 80% by weight of filler, from 5 to 30%by weight of pigments and from 0.1 to 10% by weight of furtheradditives, with the percentages by weight in the formulation adding upto 100% by weight.

Examples of fillers which can be used are carbonates such as calciumcarbonate in the form of dolomite, calcite and chalk. Further examplesare silicates such as magnesium silicate in the form of talc, oraluminum silicates such as clays; quartz flour, silica sand, finelydivided silica, feldspar, barite and gypsum. Fibrous fillers are alsosuitable. Mixtures of various fillers are frequently used in practice,for example mixtures of fillers having different particle sizes ormixtures of carbonaceous and siliceous fillers. In the latter case, aformulation whose filler has a proportion of more than 50% by weight, inparticular more than 75% by weight, based on the total amount of filler,of carbonate or silicate is referred to as carbonate-rich orsilicate-rich, respectively. Plastic renders generally contain coarserfillers than emulsion paints. The particle size is often in the rangefrom 0.2 to 5.0 mm. Otherwise, plastic renders can contain the sameadditives as emulsion paints.

Suitable pigments are, for example, titanium dioxide, zinc oxide, ironoxides, carbon black as inorganic pigments, and also the customaryorganic pigments. Examples of further additives are wetting agents inamounts of generally from 0.1 to 0.5% by weight, based on the totalweight of the formulation. Examples of these are sodium and potassiumpolyphosphates, polyacrylic acids and salts thereof. Further additiveswhich may be mentioned are thickeners which are generally used in anamount of from 0.01 to 2.0% by weight, based on the total weight of theformulation. Customary thickeners are cellulose ethers, starches andbentonites as an example of an inorganic thickener. Further additivesare preservatives, antifoams, antifreezes.

To produce the adhesives and coating compositions, the polymerdispersion of the polymer powder is mixed with the further constituentsof the formulation, viz. fillers and further additives, and homogenizedin suitable mixers. The polymer powder can, if appropriate, also beadded in the form of an aqueous redispersion on the building site. Inmany cases, a dry mix is prepared and the water necessary for processingis added immediately before processing. In the production of paste-likecompositions, a common procedure is firstly to place the appropriateamount of water in a mixing vessel, add the dispersion and finally stirin the solids.

The silicone-containing polymers are particularly advantageous asbinders in coating formulations for low-emission interior paints, inparticular those having a high PVK (highly filled paints), or ashydrophobicizing binder for renders.

The following examples serve to illustrate the invention withoutrestricting it in any way.

Preparation of the silicone-containing vinyl alcohol copolymers:

1. Preparation of vinyl acetate-polydimethylsiloxane copolymers:

EXAMPLE a

54.65 kg of ethyl acetate, 303.33 g of PDMS mixture (=Dehesive® 929),5.47 kg of isopropanol, 44.71 g of PPV (t-butyl perpivalate, 75%strength solution in aliphatics) and 2.73 kg of vinyl acetate wereplaced in a 120 l stirred vessel provided with anchor stirrer, refluxcondenser and metering facilities. The initial charge was subsequentlyheated to 75° C. at a stirrer speed of 95 rpm. After the internaltemperature of 70° C. had been reached, the metered addition ofinitiator (4.10 kg of ethyl acetate and 173.91 g of PPV) at a rate of826 g/h was commenced. Ten minutes after the start of the meteredaddition of initiator, the monomers (2.43 kg of PDMS mixture and 21.86kg of vinyl acetate) were metered in at a rate of 6.08 kg/h. The meteredaddition of initiator extended over a period of 310 minutes, while themetered addition of monomers ended 60 minutes earlier. After the end ofboth metered additions, the polymerization was continued at 70° C. for afurther 120 minutes. The polymer solution obtained was subsequentlyheated for distillation (solvent replacement), with the distillate beingreplaced every now and again by methanol. This procedure was repeateduntil the solution was free of ethyl acetate and isopropanol.

Analyses: solids content (SC): 45.6% (in methanol), GC analysis:residual VAc content: 20 ppm, residual ethyl acetate: 1100 ppm, acidnumber (AN): 3.36 mg KOH/g, viscosity (Höppler, 10% strength solution inethyl acetate)=1.34 mPas; SEC M_(W)=13502 g/mol, M_(n)=5075 g/mol,polydispersity=2.66;

glass transition temperature (T_(g)): T_(g)=30.1° C. Composition of theresin according to ¹H NMR (CDCl₃) 10.75% by weight (12.28 mol %) ofPDMS, 89.25% by weight (87.72 mol %) of PVAc.

EXAMPLE b

51.57 kg of ethyl acetate, 481.63 g of PDMS mixture (Dehesive 929), 8.09kg of isopropanol, 51.78 g of PPV (t-butyl perpivalate, 75% strengthsolution in aliphatics) and 2.53 kg of vinyl acetate were placed in a120 l stirred vessel provided with anchor stirrer, reflux condenser andmetering facilities. The initial charge was subsequently heated to 70°C. at a stirrer speed of 95 rpm. After the internal temperature of 70°C. had been reached, the metered addition of initiator (4.07 kg of ethylacetate and 201.33 g of PPV) at a rate of 827 g/h was commenced. Tenminutes after the start of the metered addition of initiator, themonomers (3.86 kg of PDMS mixture and 20.25 kg of vinyl acetate) weremetered in at a rate of 6.03 kg/h. The metered addition of initiatorextended over a period of 310 minutes, while the metered addition ofmonomers ended 60 minutes earlier. After the end of both meteredadditions, the polymerization was continued at 70° C. for a further 120minutes. The polymer solution obtained was subsequently heated fordistillation (solvent replacement), with the distillate being replacedevery now and again by methanol. This procedure was repeated until thesolution was free of ethyl acetate and isopropanol.

Analyses: SC: 50.0% (in methanol), GC analysis: residual VAc content:420 ppm, residual ethyl acetate: 1.06%, acid number: 2.80 mg KOH/g,viscosity (Höppler, 10% strength solution in ethyl acetate)=1.39 mPas;

SEC M_(W)=13640 g/mol, M_(n)=4497 g/mol, polydispersity=3.03;

glass transition temperature (T_(g)): T_(g)=28.6° C. Composition of theresin according to ¹H NMR (CDCl₃): 17.46% by weight (19.75 mol %) ofPDMS, 82.54% by weight (80.25 mol %) of PVAc.

EXAMPLE c

49.97 kg of ethyl acetate, 651.01 g of PDMS mixture (Dehesive 929), 9.38kg of isopropanol, 58.88 g of PPV (t-butyl perpivalate, 75% strengthsolution in aliphatics) and 2.34 kg of vinyl acetate were placed in a120 l stirred vessel provided with anchor stirrer, reflux condenser andmetering facilities. The initial charge was subsequently heated to 70°C. at a stirrer speed of 95 rpm. After the internal temperature of 70°C. had been reached, the metered addition of initiator (4.05 kg of ethylacetate and 228.88 g of PPV) at a rate of 829 g/h was commenced. Tenminutes after the start of the metered addition of initiator, themonomers (5.21 kg of PDMS mixture and 18.77 kg of vinyl acetate) weremetered in at a rate of 6.0 kg/h. The metered addition of initiatorextended over a period of 310 minutes, while the metered addition ofmonomers ended 60 minutes earlier. After the end of both meteredadditions, the polymerization was continued at 70° C. for a further 120minutes. The polymer solution obtained was subsequently heated fordistillation (solvent replacement), with the distillate being replacedevery now and again by methanol. This procedure was repeated until thesolution was free of ethyl acetate and isopropanol.

Analyses: SC: 52.9% (in methanol), GC analysis: residual VAc content: 60ppm, residual ethyl acetate: 2.0%, AN: 2.24 mg KOH/g, viscosity(Höppler, 10% strength solution in ethyl acetate)=1.23 mPas; SECM_(W)=10777 g/mol, M_(n)=3626 g/mol, polydispersity=2.97;

glass transition temperature (T_(g)): T_(g)=26.2° C. Composition of theresin according to ¹H NMR (CDCl₃): 22.56% by weight (25.31 mol %) ofPDMS, 77.44% by weight (74.69 mol %) of PVAc.

2. Hydrolysis of the vinyl acetate-polydimethylsiloxane copolymers toproduce the silicone-containing vinyl alcohol copolymers:

EXAMPLE d 17.8% by Weight of Silicone

26.3 kg of a 45.6% strength polymer solution in methanol, prepared asdescribed in Example a), were placed in a 120 l stirred vessel(atmospheric pressure) provided with reflux condenser, meteringfacilities and an anchor stirrer and diluted to an SC of about 20% withmethanol. This solution was then heated to 35° C. 220 ml of 45% strengthaqueous/methanolic sodium hydroxide were subsequently added quickly. 11minutes after the addition of the alkali, the mixture was set to a pH ofabout 7 by means of concentrated acetic acid. To obtain the precipitatedpolyvinyl alcohol as an aqueous solution, the suspension was heated fordistillation and the distillate was gradually replaced by water. Thisprocedure was repeated until all of the methanol had been replaced bywater.

Aqueous PVA Solution—Analyses:

SC: 11.3%; AM: 0 mg KOH/g; pH (4% strength in water): 6.5;saponification number (SN): 87.15 mg KOH/g;

VOC (volatile organic compounds) (methanol): 8 ppm Composition accordingto ¹H-NMR (in DMSO with trifluoroacetic acid as shift reagent): 13.9% byweight (8.2 mol %) of vinyl acetate, 68.3% by weight (79.5 mol %) ofvinyl alcohol, 17.8% by weight (12.3 mol %) of PDMS.

EXAMPLE e 26.0% by Weight of Silicone

Procedure as in Example d), but a hydrolysis time of 13 minutes. Theresin from Example b) was hydrolyzed.

Aqueous PVA Solution—Analyses:

SC: 11.4%; AN: 0 mg KOH/g; pH (4% strength in water) 6.74; CN: 96.33 mgKOH/g;

VOC (methanol): 590 ppm Composition according to ¹H NMR (in DMSO withtrifluoroacetic acid as shift reagent): 15.0% by weight (9.3 mol %) ofvinyl acetate, 59.0% by weight (71.8 mol %) of vinyl alcohol; 26.0% byweight (18.9 mol %) of PDMS.

EXAMPLE f 31.3% by Weight of Silicone

Procedure as in Example d), but a hydrolysis time of 11 minutes. Theresin from Example c) was hydrolyzed.

Aqueous PVA Solution—Analyses:

SC: 10.95%; AN: 0 mg KOH/g; pH (4% strength in water): 6.79; CN: 45.5 mgKOH/g;

VOC (methanol): not determined Composition according to ¹H NMR (in DMSOwith trifluoroacetic acid as shift reagent): 5.4% by weight (3.2 mol %)of vinyl acetate, 63.3% by weight (74.8 mol %) of vinyl alcohol; 31.3%by weight (22.0 mol %) of PDMS.

Preparation of polymer dispersions and polymer powders using thesilicone-containing polyvinyl alcohols:

Raw materials:

-   Genapol X 150:-   ethoxylated isotridecyl alcohol having a degree of ethoxylation of    15.    Mersolat:-   Na alkylsulfonate having from 12 to 14 carbon atoms in the alkyl    radical.    Airvol 513:-   commercial polyvinyl alcohol (from Air Products & Chemicals) having    a viscosity of about 14 mPas (20° C., 4% strength solution, measured    by the Höppler method) and a saponification number of 140 (mg KOH/g    of polymer) (degree of hydrolysis: 88 mol %).    G04/140:-   commercial polyvinyl alcohol (from Clariant) having a viscosity of    about 4 mPas (20° C., 4% strength solution, measured by the Höppler    method) and a saponification number of 140 (mg KOH/g of polymer)    (degree of hydrolysis: 88 mol %).    Polyvinyl alcohol W25/140:-   polyvinyl alcohol having a viscosity of about 25 mPas (20° C., 4%    strength solution, measured by the Höppler method) and a    saponification number of 140 (mg KOH/g of polymer) (degree of    hydrolysis: 88 mol %).    Genapol PF80:-   EO-PO block polymer containing 80% of EO.    PDMS mixture (Dehesive® 929):

Mixture of three polydimethylsiloxanes having about 100 SiOMe₂ unitswhich comprises about 5% by weight of unfunctionalizedpolydimethylsiloxane, 20% by weight of α-monovinyl-functionalizedpolydimethylsiloxane and 75% by weight of α,ω-divinyl-functionalizedpolydimethylsiloxane.

COMPARATIVE EXAMPLE 1

Vinyl acetate-ethylene-vinylsilane-GMA Copolymer Stabilized withPolyvinyl Alcohol (Without Silicone-Containing Vinyl Alcohol Copolymer)

3.64 kg of water, 177.44 g of Genapol X 150 (40% strength aqueoussolution), 164.52 g of Mersolat (40% strength aqueous solution), 70.97 gof sodium vinylsulfonate (25% strength) and 887.18 g of vinyl acetatewere placed in a 19 l pressure autoclave. The pH was set to 5 by meansof 10% strength formic acid. In addition, 9.7 ml of Trilon B (EDTA; 2%strength aqueous solution) and 30.6 ml of ammonium iron sulfate (1%strength solution) were added. The vessel was heated to 70° C. andpressurized with 22 bar of ethylene. As soon as the reactor was inthermal equilibrium, 68 g/h of a 5.4% strength ammonium peroxodisulfatesolution (APS solution) and 85 g/h of a 4.16% strength sodium sulfitesolution were fed in. 25 minutes later, introduction of a mixture of6.92 kg of vinyl acetate and 45.26 g of vinyl trimethylsiloxane (WackerSilan XL 10) at a rate of 1202 g/h (metered addition of monomer) wascommenced.

At the same time, an emulsifier mixture was fed in at a rate of 331 g/h.The emulsifier mixture comprised 385.92 g of water, 931.54 g of GenapolX 150 (40% strength aqueous solution) and 501.26 g of G 04/140(polyvinyl alcohol; 20% strength solution).

The total time over which the monomer was metered in was 5.8 h and thatover which the emulsifier was metered in was 5.5 h.

15 minutes after commencement of the reaction, the rate of addition ofthe APS was reduced to 42.2 g/h, and the rate of addition of the Nasulfite was reduced to 52.7 g/h.

30 minutes after the end of the metered addition of emulsifier, the “GMAmixture” was fed in. Composition of the “GMA mixture”: 177.44 g of vinylacetate and 53.23 g of glycidyl methacrylate. The time of addition was30 minutes (rate: 462 g/h). After the end of the metered addition of the“GMA mixture”, the introduction of APS and Na sulfite was continued for1 hour. After depressurization, the dispersion was treated with steam(“stripped”) to minimize the amount of residual monomers, and Hydorol Wwas subsequently added as preservative.

Dispersion analyses: see Table 1

COMPARATIVE EXAMPLE 2

Vinyl acetate-VeoVa-ethylene-vinylsilane-GMA-PDMS Copolymer Stabilizedwith Polyvinyl Alcohol (without Silicone-Containing Vinyl AlcoholCopolymer)

76.80 kg of water, 27.12 kg of W 25/140 (polyvinyl alcohol; 10% strengthsolution), 4.80 kg of Genapol X 150 (40% strength aqueous solution),3.44 kg of Mersolat (40% strength aqueous solution), 1.92 kg of sodiumvinylsulfonate (25% strength), 18.00 kg of vinyl acetate, 4.80 kg ofPDMS mixture and 18.00 kg of VeoVa 10 were placed in a 572 l pressureautoclave. The pH was set to 5 by means of 10% strength formic acid. Inaddition, 314 ml of Trilon B (EDTA; 2% strength aqueous solution) and991 ml of ammonium iron sulfate (1% strength solution) were added. Thevessel was heated to 70° C. and pressurized with 13 bar of ethylene. Assoon as the reactor was in thermal equilibrium, 1023 g/h of a 10.0%strength ammonium peroxodisulfate solution (APS solution) and 1976 g/hof a 5.05% strength sodium sulfite solution were fed in. 25 minuteslater, introduction of a mixture of 166.80 kg of vinyl acetate, 29.28 kgof VeoVa 10 and 1.22 kg of vinyl trimethoxysiloxane (Wacker Silan XL 10)at a rate of 34.02 kg/h (metered addition of monomer) was commenced.

At the same time, an emulsifier mixture was fed in at a rate of 12.89kg/h. The emulsifier mixture comprised 45.69 g of water and 25.20 kg ofGenapol X 150 (40% strength aqueous solution). The total time over whichthe monomer was metered in was 5.8 h and that over which the emulsifierwas metered in was 5.5 h. 15 minutes after commencement of the reaction,the rate of addition of the APS was reduced to 636 g/h, and the rate ofaddition of the Na sulfite was reduced to 1226 g/h.

30 minutes after the end of the metered addition of emulsifier, the “GMAmixture” was fed in. Composition of the “GMA mixture”: 4.80 kg of vinylacetate, 720.01 g of VeoVa 10 and 2.88 kg of glycidyl methacrylate. Thetime of addition was 30 minutes (rate: 16.8 kg/h). After the end of themetered addition of the “GMA mixture”, the introduction of APS and Nasulfite was continued for 1 hour. After depressurization, the dispersionwas treated with steam (“stripped”) to minimize the amount of residualmonomers, and Hydorol W was subsequently added as preservative.

Dispersion analyses: see Table 1

COMPARATIVE EXAMPLE 3

Vinyl acetate-ethylene-vinylsilane-GMA Copolymer Stabilized withPolyvinyl Alcohol (without Silicone-Containing Vinyl Alcohol Copolymer):

102.99 kg of water, 17.90 kg of Genapol X 150 (40% strength aqueoussolution), 3.54 kg of Mersolat (40% strength aqueous solution), 1.97 kgof sodium vinylsulfonate (25% strength), 13.95 kg of W 25/140 (polyvinylalcohol, 10% strength in water) and 24.69 kg of vinyl acetate wereplaced in a 572 l pressure autoclave. The pH was set to 5 by means of10% strength formic acid. In addition, 314 ml of Trilon B (EDTA; 2%strength aqueous solution) and 991 ml of ammonium iron sulfate (1%strength solution) were added. The vessel was heated to 70° C. andpressurized with 22 bar of ethylene. As soon as the reactor was inthermal equilibrium, 1023 g/h of a 10.0% strength ammoniumperoxodisulfate solution (APS solution) and 1976 g/h of a 5.05% strengthsodium sulfite solution were fed in. 25 minutes later, introduction of amixture of 217.25 kg of vinyl acetate and 1.25 kg of vinyltrimethoxysiloxane (Wacker Silan XL 10) at a rate of 41.23 kg/h (meteredaddition of monomer) was commenced. At the same time, an emulsifiermixture was fed in at a rate of 9.85 kg/h. The emulsifier mixturecomprised 22.34 kg of water, 12.96 kg of Genapol X 150 (40% strengthaqueous solution) and 13.95 kg of W 25/140 (polyvinyl alcohol; 10%strength solution).

The total time over which the monomer was metered in was 5.3 h and thatover which the emulsifier was metered in was 5.0 h.

15 minutes after commencement of the reaction, the rate of addition ofthe APS was reduced to 636 g/h, and the rate of addition of the Nasulfite was reduced to 1226 g/h.

30 minutes after the end of the metered addition of emulsifier, the “GMAmixture” was fed in. Composition of the “GMA mixture”: 4.94 kg of vinylacetate and 1.48 kg of glycidyl methacrylate. The time of addition was30 minutes (rate: 12.84 kg/h). After the end of the metered addition ofthe “GMA mixture”, the introduction of APS and Na sulfite was continuedfor 1 hour. After depressurization, the dispersion was treated withsteam (“stripped”) to minimize the amount of residual monomers, andHydorol W was subsequently added as preservative.

Dispersion analyses: see Table 1

COMPARATIVE EXAMPLE 4

Vinyl acetate-ethylene-vinylsilane-GMA Copolymer Stabilized withPolyvinyl Alcohol (without Silicone-Containing Vinyl Alcohol Copolymer)

3.53 kg of water, 176.30 g of Genapol X 150 (40% strength aqueoussolution), 163.47 g of Mersolat (40% strength aqueous solution), 70.52 gof sodium vinylsulfonate (25% strength) and 881.52 g of vinyl acetatewere placed in a 19 liter pressure autoclave. The pH was set to 5 bymeans of 10% strength formic acid. In addition, 9.7 ml of Trilon B(EDTA; 2% strength aqueous solution) and 30.6 ml of ammonium ironsulfate (1% strength solution) were added. The vessel was heated to 70°C. and pressurized with 22 bar of ethylene. As soon as the reactor wasin thermal equilibrium, 68 g/h of a 5.4% strength ammoniumperoxodisulfate solution (APS solution) and 85 g/h of a 4.16% strengthsodium sulfite solution were fed in. 25 minutes later, introduction of amixture of 6.88 kg of vinyl acetate and 44.98 g of vinyltrimethoxysiloxane (Wacker Silan XL 10) at a rate of 1194 g/h (meteredaddition of monomer) was commenced.

At the same time, an emulsifier mixture was fed in at a rate of 359 g/h.The emulsifier mixture comprised 925.60 g of Genapol X 150 (40% strengthaqueous solution) and 1050 g of Airvol V513 (polyvinyl alcohol; 9.5%strength solution).

The total time over which the monomer was metered in was 5.8 h and thatover which the emulsifier was metered in was 5.5 h.

15 minutes after conmiencement of the reaction, the rate of addition ofthe APS was reduced to 4.2 g/h, and the rate of addition of the Nasulfite was reduced to 52.7 g/h.

30 minutes after the end of the metered addition of emulsifier, the “GMAmixture” was fed in. Composition of the “GMA mixture”: 176.30 g of vinylacetate and 52.89 g of glycidyl methacrylate. The time of addition was30 minutes (rate: 459 g/h). After the end of the metered addition of the“GMA mixture”, the introduction of APS and Na sulfite was continued for1 hour. After depressurization, the dispersion was treated with steam(“stripped”) to minimize the amount of residual monomers, and Hydorol Wwas subsequently added as preservative.

Dispersion Analyses: see Table 1

EXAMPLE 1

Procedure as in Comparative example 1. Only 100.11 g of thesilicone-containing polyvinyl alcohol from Example d) were used in placeof the polyvinyl alcohol G04/140.

Dispersion Analyses: see Table 1.

EXAMPLE 2

Procedure as in Comparative example 1. Only 100.16 g of thesilicone-containing polyvinyl alcohol from Example e) were used in placeof the polyvinyl alcohol G04/140.

Dispersion Analyses: see Table 1.

EXAMPLE 3

Vinyl acetate-ethylene-vinylsilane-GMA Copolymer Stabilized withPolyvinyl Alcohol and with a Silicone-Containing Vinyl Alcohol Copolymeras Protective Colloid

2.08 kg of water, 204.12 g of Genapol X 150 (40% strength aqueoussolution), 151.41 g of Mersolat (40% strength aqueous solution), 809.32g of silicone-containing polyvinyl alcohol from Example e) (11.4% inwater), 65.32 g of sodium vinylsulfonate (25% strength) and 816.48 g ofvinyl acetate were placed in a 19 l pressure autoclave. The pH was setto 5 by means of 10% strength formic acid. In addition, 9.7 ml of TrilonB (EDTA; 2% strength aqueous solution) and 30.6 ml of ammonium ironsulfate (1% strength solution) were added. The vessel was heated to 70°C. and pressurized with 22 bar of ethylene. As soon as the reactor wasin thermal equilibrium, 68 g/h of a 5.4% strength ammoniumperoxodisulfate solution (APS solution) and 85 g/h of a 4.16% strengthsodium sulfite solution were fed in. 25 minutes later, introduction of amixture of 7.19 kg of vinyl acetate and 41.66 g of vinyltrimethylsiloxane (Wacker Silan XL 10) at a rate of 1247 g/h (meteredaddition of monomer) was commenced.

At the same time, an emulsifier mixture was fed in at a rate of 464 g/h.The emulsifier mixture comprised 919.14 g of water and 1.63 kg ofGenapol PF 80 (20% strength aqueous solution).

The total time over which the monomer was metered in was 5.8 h and thatover which the emulsifier was metered in was 5.5 h.

15 minutes after commencement of the reaction, the rate of addition ofthe APS was reduced to 42.2 g/h, and the rate of addition of the Nasulfite was reduced to 52.7 g/h.

30 minutes after the end of the metered addition of emulsifier, the “GMAmixture” was fed in. Composition of the “GMA mixture”: 163.3 g of vinylacetate and 48.99 g of glycidyl methacrylate. The time of addition was30 minutes (rate: 425 g/h). After the end of the metered addition of the“GMA mixture”, the introduction of APS and Na sulfite was continued for1 hour. After depressurization, the dispersion was treated with steam(“stripped”) to minimize the amount of residual monomers, and Hydorol Wwas subsequently added as preservative.

Dispersion Analyses: see Table 1

EXAMPLE 4

Procedure as in Example 3. Only 92.22 g of the silicone-containingpolyvinyl alcohol from Example d) were used in place of thesilicone-containing polyvinyl alcohol from Example e).

Dispersion Analyses: see Table 1.

EXAMPLE 5

Procedure as in Comparative example 2. Only 2.72 kg of thesilicone-containing polyvinyl alcohol from Example d) were used in placeof W25/140. Furthermore, 14 bar of ethylene were injected.

Dispersion Analyses: see Table 1.

EXAMPLE 6

Procedure as in Comparative example 2. Only 2.71 kg of thesilicone-containing polyvinyl alcohol from Example e) were used in placeof W25/140. Furthermore, 14 bar of ethylene were injected.

Dispersion Analyses: see Table 1.

EXAMPLE 7

Procedure as in Comparative example 0.2. Only 2.71 kg of thesilicone-containing polyvinyl alcohol from Example f) were used in placeof W25/140. Furthermore, 14 bar of ethylene were injected.

Dispersion Analyses: see Table 1.

EXAMPLE 8

The dispersion from Example 7 was admixed with 5% by weight(solid/solid) of the silicone-containing polyvinyl alcohol from Examplef) and diluted with water to an atomization viscosity of 250 mPas. Thedispersion was then sprayed by means of a two-fluid nozzle. Air whichhad been precompressed to 4 bar served as atomization component, and thedroplets formed were dried in cocurrent by means of air heated to 125°C. The dried powder obtained was admixed with 10% by weight ofcommercial antiblocking agent (mixture of calcium-magnesium carbonateand magnesium hydrosilicate). A white, free-flowing powder was obtained.

As can be seen from Table 1, the silicone-containing polyvinyl alcohols(vinyl alcohol-PDMS copolymer or vinyl acetate-vinyl alcohol-PDMSterpolymer) prepared in the examples are best suited for use in theemulsion polymerization.

This demonstrated by comparison of comparative examples C1 to C4, whichwere prepared using the commercial polyvinyl alcohols which havepreviously been found to be useful in emulsion polymerization, withExamples 1 to 7 which were prepared using silicone-containing polyvinylalcohols.

When these are used, dispersions having an advantageous particle sizedistribution were obtained and coagulum formation was not observed inany of the examples. The viscosity can be varied over a wide range bymeans of the molecular weight of the polyvinyl alcohol (cf. Comparativeexamples C1, C3, C4).

TABLE 1 Dispersion analyses BF 20 Ex. T_(g) ° C. pH mPas D nm Dn μm Dvμm SA m² SC % C1 9.6 4.83 385 275 0.219 0.451 20.0 58.8 C2 9.2 5.18 3220390 0.08 0.759 16.7 58.0 C3 10.3 5.15 8400 317 0.08 0.314 26.7 59.7 C49.3 5.34 585 267 0.209 0.493 19.9 58.9 1 9.0 4.9 212.5 248 0.127 0.96823.5 59.0 2 8.6 5.23 180 256 0.219 0.452 21.1 60.2 3 12.2 4.3 4040 2270.111 0.175 39.2 58.1 4 12.4 5.5 1360 289 0.275 0.312 20.0 60.9 5 8.05.4 294 234 0.102 1.323 25.7 59.1 6 8.7 5.3 274 250 0.109 1.439 26.158.8 7 6.8 5.2 293 229 0.137 0.180 36.4 56.9 BF 20 = Brookfieldviscosity, D = mean particle size (Nanosizer), Dn = mean particle size(number average, Coulter Counter), Dv = mean particle size (volumeaverage, Coulter Counter), SA = particle surface area per g of polymerdispersion, SC = solids content.

The dispersions were used to produce paints according to a silicate-richformulation 1 and a carbonate-rich formulation 2 as per the formulationsshown below (Tables 2 and 3):

TABLE 2 Paint formulation 1 (silicate-rich): Water 350 Cellulose ether(Tylose MH 10000 KG4) 5 Dispersant (Dispex N 40) 2 Magnesium silicate(talc N) 100 Magnesium silicate (Chinaclay Grade B) 100 Titanium dioxidepigment (Kronos 2300) 100 Calcium carbonate (Omyacarb 5 GU) 200 Ammonia0.5 Polymer dispersion (SC 60%) 142.5 Total parts by weight 1000

TABLE 3 Paint formulation 2 (carbonate-rich): Water 350 Cellulose ether(Tylose MH 10000 KG4) 5 Dispersant (Dispex N 40) 2 Titanium dioxidepigment (Kronos 2300) 100 Calcium carbonate (Omyacarb 5 GU) 400 Ammonia0.5 Polymer dispersion (SC 60%) 142.5 Total parts by weight 1000Use Tests:Testing of the Hydrophobicity by Means of the Water Drop Test

A paint produced according to the above formulations 1 and 2 was appliedto Eterplan (commercial fibrocement sheet) (layer thickness: about 400μm). After drying, 1 ml of water was placed in the form of a drop on thecoating by means of a syringe after one day. The time (in minutes) untilthe drop had spread and thus disappeared was recorded. The longer thistime, the higher the hydrophobicity and the water resistance of thepaint or the dispersion present therein. In the case of a veryhydrophobic dispersion, the drop remains for a number of hours.

Table 4 shows the use data.

TABLE 4 Hydrophobicity Hydrophobicity Formulation 2 after Formulation 1after Example 1 day in min 1 day in min C1  60  55 C2 180 190 C3  90  80C4  60  50 1 250 270 2 280 320 3 255 320 4 250 270 5 270 320 6 280 350 7360 410

The following can be seen from Table 4:

Comparison of Comparative examples C1, C3 and C4 (commerial polyvinylalcohols) with Examples 1 to 4 (silicone-containing polyvinyl alcoholsfrom Examples d) and e)) shows that the hydrophobicity can be increasedsignificantly by means of the silicone-containing polyvinyl alcohols.The increase is by a factor of from 3 to 6. In the case of Comparativeexample C2, a silicone macromer was additionally polymerized into thepolymer. This generally leads to an increase in the hydrophobicity.However, comparison with Examples 5, 6 and 7 (likewise withcopolymerized silicone macromer) shows that in such systems, too, thehydrophobicity can be additionally increased noticeably by a use of asilicone-containing polyvinyl alcohol.

Comparison of Example 4 (emulsifier: Genapol PF 80) with Example 1(emulsifier: Genapol X150) (in each case silicone-containing polyvinylalcohol from Example d)=PVAL with 17.8% by weight of silicone) andcomparison of Example 3 (emulsifier: Genapol PF 80) with Example 2(emulsifier: Genapol X150) (in each case silicone-containing polyvinylalcohol from Example e); PVAL with 26.0% by weight of silicone) showsthat exchange of emulsifiers, in this case Genapol X150 versus GenapolPF80, has no appreciable influence on the hydrophobicity.

Comparison of Example 1 (PVAL with 17.8% by weight of silicone; fromExample d)) with Example 2 (PVAL with 26.0% by weight of silicone; fromExample e)) and of Example 4 (PVAL with 17.8% by weight of silicone;from Example d)) with Example 3 (PVAL with 26.0% by weight of silicone;from Example e)) shows that the hydrophobicity increases with anincreased silicone content in the silicone-containing PVAL used forpreparing the dispersion. This is also demonstrated very clearly by, inparticular, the series Example 5 (PVAL with 17.8% by weight of silicone;from Example d)), Example 6 (PVAL with 26.0% by weight of silicone; fromExample e)) and Example 7 (PVAL with 31.3% by weight of silicone; fromExample f)).

Starting up from a dispersion prepared using the silicone-containingpolyvinyl alcohols, the addition of a copolymerizable silicone macromerleads to a slight increase in the hydrophobicity. This is demonstratedby comparison of Example 1 (PVAL with 17.8% by weight of silicone;without silicone macromer) and of Example 4 (PVAL with 17.8% by weightof silicone, without silicone macromer) with Example 5 (PVAL with 17.8%by weight of silicone; with silicone macromer in the dispersion). It isalso demonstrated by comparison of Example 2 (PVAL with 26.0% by weightof silicone; without silicone macromer) and of Example 3 (PVAL with26.0% by weight of silicone, without silicone macromer) with Example 6(PVAL with 26.0% by weight of silicone; with silicone macromer in thedispersion). However, the main influence on the increase in thehydrophobicity comes from the use of silicone-containing polyvinylalcohols; the additional use of silicone macromers brings only arelatively slight improvement in the hydrophobicity.

1. A process for preparing silicone-modified polymers in the form of anaqueous polymer dispersion or polymer powder prepared therefrom, bymeans of free-radical polymerization of ethylenically unsaturatedmonomers in an aqueous medium, comprising polymerizing a polymerizablemixture containing at least one monomer selected from the groupconsisting of vinyl esters of unbranched or branched C₁₋₁₅alkylcarboxylic acids, methacrylic esters and acrylic esters of C₁₋₁₅alcohols, vinyl aromatics, monoolefins, dienes and vinyl halides, toform an addition polymer, and optionally, further auxiliary monomers toform a dispersed phase, and wherein at least one silicone-containingvinyl alcohol copolymer prepared from monomers comprising a) from 0 to60% by weight of units of one or more vinyl esters of unbranched orbranched C₁₋₁₅ alkylcarboxylic acids, b) from 20 to 99.5% by weight ofvinyl alcohol units, c) from 0.5 to 70% by weight of units of one ormore silicones having the general formula R¹_(a)R_(3-a)SiO(SiR₂O)_(n)SiR_(3-a)R¹ _(a), where the radicals R areidentical or different and are each a monovalent, substituted orunsubstituted alkyl or alkoxy radical each having from 1 to 18 carbonatoms, R¹ is a polymerizable group, a is 0 or 1, and n is from 10 to1000, where at least one silicone contains at least one radical R¹ thepercentages by weight add up to 100% by weight, is present duringpolymerization, is present during polymerization and added followingpolymerization, or is added following polymerization and the resultingmixture is spray dried to form a polymer powder.
 2. The process of claim1, wherein said silicone-containing polyvinylalcohol copolymer ispresent prior to commencement of polymerization, or not prior tocommencement of polymerization but present during polymerization.
 3. Theprocess of claim 1, wherein said silicone-containing polyvinylalcoholcopolymer is added after polymerization and prior to spray drying toform a polymer powder.
 4. The process of claim 1, wherein thesilicone-containing vinyl alcohol copolymer contains vinyl acetateunits.
 5. The process of claim 1, wherein the silicone-containing vinylalcohol copolymer contains silicone units c) derived from silicones inwhich R¹ is an alkenyl radical having from 2 to 8 carbon atoms.
 6. Theprocess of claim 5, wherein the silicone-containing vinyl alcoholcopolymer comprises silicone units c) derived from at least one siliconeselected from the group consisting of α-monovinylpolydimethylsiloxanes,α-mono(3-acryloxypropyl)polydimethylsiloxanes,α-mono(acryloxymethyl)polydimethylsiloxanes,α-mono(3-methacryloxypropyl)polydimethylsiloxanes, α,ω-divinylpolydimethylsiloxanes, α,ω-di(3-acryloxypropyl)polydimethylsiloxanes, and α,ω-di(3-methacryloxypropyl)polydimethylsiloxanes.
 7. The process of claim1, wherein vinyl acetate; mixtures comprising vinyl acetate andethylene, mixtures comprising vinyl acetate and further vinyl esters andoptionally ethylene; mixtures comprising vinyl acetate, ethylene, andvinyl chloride; vinyl ester mixtures containing acrylic esters;(meth)acrylic ester mixtures; or mixtures comprising styrene andbutadiene or (meth)acrylic esters, are polymerized as ethylenicallyunsaturated monomers.
 8. The process of claim 7, wherein mixturescomprising vinyl acetate and ethylene, or mixtures comprising vinylacetate, ethylene, and vinyl esters of an α-branched carboxylic acidhaving 9 or 10 carbon atoms, are polymerized.
 9. The process of claim 1,wherein one or more silanes selected from the group consisting ofγ-acryloxypropyltri(alkoxy)silanes,γ-methacryloxy-propyltri(alkoxy)silanes,α-methacryloxymethyltri(alkoxy)silanes,γ-methacryloxypropylmethyldi(alkoxy)silanes, vinylalkyldi(alkoxy)silanesand vinyltri(alkoxy)silanes are additionally copolymerized with theethylenically unsaturated monomers.
 10. The process of claim 1, whereinone or more epoxy-functional monomers selected from the group consistingof glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, andvinyl glycidyl ether are additionally copolymerized with theethylenically unsaturated monomers.
 11. The process of claim 1, whereinone or more silicone macromers which have at least one unsaturated groupand are selected from the group consisting of linearpolydialkylsiloxanes and branched polydialkylsiloxanes havingC₁-Chd₆-alkyl radicals and a chain length of from 10 to 1000,SiO(C_(n)H_(2n+1))₂ units and which contain one or two terminal orpendant polymerizable groups are additionally copolymerized with theethylenically unsaturated monomers.